org.geotools.data.wfs.impl

Class WFSDataAccessFactory

Object

WFSDataAccessFactory

All Implemented Interfaces:

DataAccessFactory, Factory

Direct Known Subclasses:

WFSDataStoreFactory

public class WFSDataAccessFactory
extends Object
implements DataAccessFactory

The factory responsible for creating WFSDataAccess objects based on their capabilities and the configuration file used. This file is included as a candidate for DataAccessFinder by virtue of the fact that its name is present in the file gt-wfs-ng > src/main/resources > META-INF > services > org.geotools.data.DataAccessFactory.

Author:

Adam Brown (Curtin University of Technology)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	WFSDataAccessFactory.WFSFactoryParam<T> A DataAccessFactory.Param subclass that allows us to provide a default value to the lookUp method.

Nested classes/interfaces inherited from interface DataAccessFactory

DataAccessFactory.Param

Field Summary

Fields

Modifier and Type	Field and Description
static WFSDataAccessFactory.WFSFactoryParam<String>	AXIS_ORDER Optional String DataStore parameter indicating axis order used by the remote WFS server in result coordinates.
static String	AXIS_ORDER_COMPLIANT
static String	AXIS_ORDER_EAST_NORTH Values for the AXIS_ORDER and AXIS_ORDER_FILTER connection parameters.
static WFSDataAccessFactory.WFSFactoryParam<String>	AXIS_ORDER_FILTER
static String	AXIS_ORDER_NORTH_EAST
static WFSDataAccessFactory.WFSFactoryParam<Integer>	BUFFER_SIZE Optional Integer parameter stating how many Feature instances to buffer at once.
static WFSDataAccessFactory.WFSFactoryParam<String>	ENCODING Optional String DataStore parameter supplying a JVM supported charset name to use as the character encoding for XML requests sent to the server.
static WFSDataAccessFactory.WFSFactoryParam<EntityResolver>	ENTITY_RESOLVER Optional EntityResolver used to expand XML entities during parses
static WFSDataAccessFactory.WFSFactoryParam<Integer>	FILTER_COMPLIANCE Optional Integer DataStore parameter indicating level of compliance to WFS specification XMLHandlerHints.VALUE_FILTER_COMPLIANCE_LOW XMLHandlerHints.VALUE_FILTER_COMPLIANCE_MEDIUM XMLHandlerHints.VALUE_FILTER_COMPLIANCE_HIGH
static WFSDataAccessFactory.WFSFactoryParam<Boolean>	GML_COMPATIBLE_TYPENAMES Optional Integer OCG GML compliance level. i.e.
static WFSDataAccessFactory.WFSFactoryParam<Integer>	GML_COMPLIANCE_LEVEL Optional Integer OCG GML compliance level. i.e.
static WFSDataAccessFactory.WFSFactoryParam<Boolean>	LENIENT Optional Boolean DataStore parameter indicating whether to be lenient about parsing bad data
static WFSDataAccessFactory.WFSFactoryParam<Integer>	MAXFEATURES Optional positive Integer used as a hard limit for the amount of Features to retrieve for each FeatureType.
static WFSDataAccessFactory.WFSFactoryParam<String>	NAMESPACE Optional String namespace URI to override the originial namespaces
static WFSDataAccessFactory.WFSFactoryParam<String>	OUTPUTFORMAT
static WFSDataAccessFactory.WFSFactoryParam<String>	PASSWORD Optional String DataStore parameter supplying the password to use when the server requires HTTP authentication Shall be used together with USERNAME or not used at all.
static WFSDataAccessFactory.WFSFactoryParam<Boolean>	PROTOCOL Optional Boolean DataStore parameter acting as a hint for the HTTP protocol to use preferably against the WFS instance, with the following semantics: null (not supplied): use "AUTO", let the DataStore decide.
static WFSDataAccessFactory.WFSFactoryParam<Integer>	TIMEOUT Optional Integer DataStore parameter indicating a timeout in milliseconds for the HTTP connections.
static WFSDataAccessFactory.WFSFactoryParam<Boolean>	TRY_GZIP Optional Boolean data store parameter indicating whether to set the accept GZip encoding on the HTTP request headers sent to the server
static WFSDataAccessFactory.WFSFactoryParam<URL>	URL Mandatory DataStore parameter indicating the URL for the WFS GetCapabilities document.
static WFSDataAccessFactory.WFSFactoryParam<Boolean>	USEDEFAULTSRS Optional String Flag to disable usage of OtherSRS in requests and always use DefaultSRS (eventually reprojecting locally the results)
static WFSDataAccessFactory.WFSFactoryParam<String>	USERNAME Optional String DataStore parameter supplying the user name to use when the server requires HTTP authentication Shall be used together with PASSWORD or not used at all.
static WFSDataAccessFactory.WFSFactoryParam<String>	WFS_STRATEGY Optional String DataStore parameter indicating either "mapserver", "geoserver", "strict", "nonstrict", "ionic", "cubwerx" or "arcgis" strategy

Constructor Summary

Constructors

Constructor and Description
WFSDataAccessFactory()

Method Summary

Modifier and Type	Method and Description
boolean	canProcess(Map params) Checks whether params contains a valid set of parameters to connect to a WFS.
protected boolean	canProcess(Map params, int maximumGmlComplianceLevel)
DataAccess<? extends FeatureType,? extends Feature>	createDataStore(Map<String,Serializable> params) Construct a live DataAccess using the connection parameters provided.
String	getDescription() Describe the nature of the datasource constructed by this factory.
String	getDisplayName() Name suitable for display to end user.
Map<RenderingHints.Key,?>	getImplementationHints() Map of hints (maybe unmodifiable) used by this factory to customize its use.
DataAccessFactory.Param[]	getParametersInfo() Returns the set of parameter descriptors needed to connect to a WFS.
protected WFSClient	getWFSClient(Map<String,Serializable> params)
boolean	isAvailable() Test to see if the implementation is available for use.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

AXIS_ORDER_EAST_NORTH

public static final String AXIS_ORDER_EAST_NORTH

Values for the AXIS_ORDER and AXIS_ORDER_FILTER connection parameters.

See Also:

Constant Field Values

AXIS_ORDER_NORTH_EAST

public static final String AXIS_ORDER_NORTH_EAST

See Also:

Constant Field Values

AXIS_ORDER_COMPLIANT

public static final String AXIS_ORDER_COMPLIANT

See Also:

Constant Field Values

URL

public static final WFSDataAccessFactory.WFSFactoryParam<URL> URL

Mandatory DataStore parameter indicating the URL for the WFS GetCapabilities document.

PROTOCOL

public static final WFSDataAccessFactory.WFSFactoryParam<Boolean> PROTOCOL

Optional Boolean DataStore parameter acting as a hint for the HTTP protocol to use preferably against the WFS instance, with the following semantics:

• null (not supplied): use "AUTO", let the DataStore decide.
• Boolean.TRUE use HTTP POST preferably.
• Boolean.FALSE use HTTP GET preferably.

USERNAME

public static final WFSDataAccessFactory.WFSFactoryParam<String> USERNAME

Optional String DataStore parameter supplying the user name to use when the server requires HTTP authentication

Shall be used together with PASSWORD or not used at all.

See Also:

Authenticator

PASSWORD

public static final WFSDataAccessFactory.WFSFactoryParam<String> PASSWORD

Optional String DataStore parameter supplying the password to use when the server requires HTTP authentication

Shall be used together with USERNAME or not used at all.

See Also:

Authenticator

ENCODING

public static final WFSDataAccessFactory.WFSFactoryParam<String> ENCODING

Optional String DataStore parameter supplying a JVM supported charset name to use as the character encoding for XML requests sent to the server.

TIMEOUT

public static final WFSDataAccessFactory.WFSFactoryParam<Integer> TIMEOUT

Optional Integer DataStore parameter indicating a timeout in milliseconds for the HTTP connections. <>p> @TODO: specify if its just a connection timeout or also a read timeout

BUFFER_SIZE

public static final WFSDataAccessFactory.WFSFactoryParam<Integer> BUFFER_SIZE

Optional Integer parameter stating how many Feature instances to buffer at once. Only implemented for WFS 1.0.0 support.

TRY_GZIP

public static final WFSDataAccessFactory.WFSFactoryParam<Boolean> TRY_GZIP

Optional Boolean data store parameter indicating whether to set the accept GZip encoding on the HTTP request headers sent to the server

LENIENT

public static final WFSDataAccessFactory.WFSFactoryParam<Boolean> LENIENT

Optional Boolean DataStore parameter indicating whether to be lenient about parsing bad data

MAXFEATURES

public static final WFSDataAccessFactory.WFSFactoryParam<Integer> MAXFEATURES

Optional positive Integer used as a hard limit for the amount of Features to retrieve for each FeatureType. A value of zero or not providing this parameter means no limit.

FILTER_COMPLIANCE

public static final WFSDataAccessFactory.WFSFactoryParam<Integer> FILTER_COMPLIANCE

Optional Integer DataStore parameter indicating level of compliance to WFS specification

• XMLHandlerHints.VALUE_FILTER_COMPLIANCE_LOW
• XMLHandlerHints.VALUE_FILTER_COMPLIANCE_MEDIUM
• XMLHandlerHints.VALUE_FILTER_COMPLIANCE_HIGH

WFS_STRATEGY

public static final WFSDataAccessFactory.WFSFactoryParam<String> WFS_STRATEGY

Optional String DataStore parameter indicating either "mapserver", "geoserver", "strict", "nonstrict", "ionic", "cubwerx" or "arcgis" strategy

NAMESPACE

public static final WFSDataAccessFactory.WFSFactoryParam<String> NAMESPACE

Optional String namespace URI to override the originial namespaces

USEDEFAULTSRS

public static final WFSDataAccessFactory.WFSFactoryParam<Boolean> USEDEFAULTSRS

Optional String Flag to disable usage of OtherSRS in requests and always use DefaultSRS (eventually reprojecting locally the results)

AXIS_ORDER

public static final WFSDataAccessFactory.WFSFactoryParam<String> AXIS_ORDER

Optional String DataStore parameter indicating axis order used by the remote WFS server in result coordinates.

AXIS_ORDER_FILTER

public static final WFSDataAccessFactory.WFSFactoryParam<String> AXIS_ORDER_FILTER

OUTPUTFORMAT

public static final WFSDataAccessFactory.WFSFactoryParam<String> OUTPUTFORMAT

GML_COMPLIANCE_LEVEL

public static final WFSDataAccessFactory.WFSFactoryParam<Integer> GML_COMPLIANCE_LEVEL

Optional Integer OCG GML compliance level. i.e. (simple feature) 0, 1 or 2

GML_COMPATIBLE_TYPENAMES

public static final WFSDataAccessFactory.WFSFactoryParam<Boolean> GML_COMPATIBLE_TYPENAMES

Optional Integer OCG GML compliance level. i.e. (simple feature) 0, 1 or 2

ENTITY_RESOLVER

public static final WFSDataAccessFactory.WFSFactoryParam<EntityResolver> ENTITY_RESOLVER

Optional EntityResolver used to expand XML entities during parses

Constructor Detail

WFSDataAccessFactory

public WFSDataAccessFactory()

Method Detail

canProcess

public boolean canProcess(Map params)

Checks whether params contains a valid set of parameters to connect to a WFS.

Rules are:

• The mandatory URL is provided.
• Either both USERNAME and PASSWORD are provided, or none.

Specified by:

canProcess in interface DataAccessFactory

Parameters:

params - The full set of information needed to construct a live data source.

Returns:

booean true if and only if this factory can process the resource indicated by the param set and all the required params are pressent.

canProcess

protected boolean canProcess(Map params,
                             int maximumGmlComplianceLevel)

createDataStore

public DataAccess<? extends FeatureType,? extends Feature> createDataStore(Map<String,Serializable> params)
                                                                    throws IOException

Description copied from interface: DataAccessFactory

Construct a live DataAccess using the connection parameters provided.

You can think of this class as setting up a connection to the back end data source. The required parameters are described by the getParameterInfo() method.

Magic Params: the following params are magic and are honoured by convention by the GeoServer and uDig application.

• "user": is taken to be the user name
• "passwd": is taken to be the password
• "namespace": is taken to be the namespace prefix (and will be kept in sync with GeoServer namespace management.

When we eventually move over to the use of OpperationalParam we will have to find someway to codify this convention.

Specified by:

createDataStore in interface DataAccessFactory

Parameters:

params - The full set of information needed to construct a live data store. Typical key values for the map include: url - location of a resource, used by file reading datasources. dbtype - the type of the database to connect to, e.g. postgis, mysql

Returns:

The created DataStore, this may be null if the required resource was not found or if insufficent parameters were given. Note that canProcess() should have returned false if the problem is to do with insuficent parameters.

Throws:

IOException - if there were any problems setting up (creating or connecting) the datasource.

getDescription

public String getDescription()

Description copied from interface: DataAccessFactory

Describe the nature of the datasource constructed by this factory.

A non localized description of this data store type.

Specified by:

getDescription in interface DataAccessFactory

Returns:

A human readable description that is suitable for inclusion in a list of available datasources.

getParametersInfo

public DataAccessFactory.Param[] getParametersInfo()

Returns the set of parameter descriptors needed to connect to a WFS.

Specified by:

getParametersInfo in interface DataAccessFactory

Returns:

Param array describing the Map for createDataStore

See Also:

DataAccessFactory.getParametersInfo(), URL, NAMESPACE, PROTOCOL, USERNAME, PASSWORD, TIMEOUT, BUFFER_SIZE, TRY_GZIP, LENIENT, ENCODING, FILTER_COMPLIANCE, MAXFEATURES, WFS_STRATEGY

getWFSClient

protected WFSClient getWFSClient(Map<String,Serializable> params)
                          throws IOException

Throws:

IOException

getImplementationHints

public Map<RenderingHints.Key,?> getImplementationHints()

Description copied from interface: Factory

Map of hints (maybe unmodifiable) used by this factory to customize its use. This map is not guaranteed to contains all the hints supplied by the user; it may be only a subset. Consequently, hints provided here are usually not suitable for creating new factories, unless the implementation make some additional garantees (e.g. FactoryUsingVolatileDependencies).

The primary purpose of this method is to determine if an existing factory instance can be reused for a set of user-supplied hints. This method is invoked by FactoryRegistry in order to compare this factory's hints against user's hints. This is dependency introspection only; FactoryRegistry never invokes this method for creating new factories.

Keys are usually static constants from the Hints class, while values are instances of some key-dependent class. The key set must contains at least all hints impacting functionality. While the key set may contains all hints supplied by the user, it is recommended to limit the set to only the hints used by this particular factory instance. A minimal set will helps FactoryRegistry to compare only hints that matter and avoid the creation of unnecessary instances of this factory.

The hint values may be different than the one supplied by the user. If a user supplied a hint as a Class object, this method shall replace it by the actual instance used, if possible.

Implementations of this method are usually quite simple. For example if a datum authority factory uses an ordinary datum factory, its method could be implemented as below (note that we should not check if the datum factory is null, since key with null value is the expected behaviour in this case). Example:

 Map hints = new HashMap();
 hints.put(Hints.DATUM_FACTORY, datumFactory);
 return hints;
 

Specified by:

getImplementationHints in interface Factory

Returns:

The map of hints, or an empty map if none.

getDisplayName

public String getDisplayName()

Description copied from interface: DataAccessFactory

Name suitable for display to end user.

A non localized display name for this data store type.

Specified by:

getDisplayName in interface DataAccessFactory

Returns:

A short name suitable for display in a user interface.

isAvailable

public boolean isAvailable()

Description copied from interface: DataAccessFactory

Test to see if the implementation is available for use. This method ensures all the appropriate libraries to construct the DataAccess are available.

Most factories will simply return true as GeoTools will distribute the appropriate libraries. Though it's not a bad idea for DataStoreFactories to check to make sure that the libraries are there.

OracleDataStoreFactory is an example of one that may generally return false, since GeoTools can not distribute the oracle jars. (they must be added by the client.)

One may ask how this is different than canProcess, and basically available is used by the DataStoreFinder getAvailableDataStore method, so that DataStores that can not even be used do not show up as options in gui applications.

Specified by:

isAvailable in interface DataAccessFactory

Returns:

true if and only if this factory has all the appropriate jars on the classpath to create DataStores.